1 88 MORPHOLOGY OF INVERTEBRATE TYPES 



5. Remove with scissors the entire aboral wall of the disc. 

 Remove with a forceps all organs. Make a drawing showing 

 teeth, oral pentagon, vertebrae of the arms, genital pouches of 

 the interradii and genital slits. 



6. Break off an arm and examine the exposed cross-section 

 under dissecting microscope. Make a quarter page drawing 

 showing dorsal, ventral, two lateral plates with spines, vertebra, 

 ambulacral tentacles. 



